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Clark Zinzow commented on ARROW-7245: ------------------------------------- +1 to having `Concatenate` going through the type promotion logic in the compute layer; I'm currently running into a similar issue with concatenating tables with different numeric types that can certainly be promoted to a common numeric type. I'm currently working around this in application code by doing manual type promotion of each column to the common dtype across that column in all tables (mimicking Arrow's internal type promotion logic [here|https://github.com/apache/arrow/blob/6cc37cf2d1ba72c46b64fbc7ac499bd0d7296d20/cpp/src/arrow/compute/kernels/codegen_internal.cc#L145-L338])) before concatenating the tables. Here is a pyarrow MRP: ```python In [1]: t1 = pa.table({"a": pa.array([1, 2], type=pa.int16())}) In [2]: t2 = pa.table({"a": pa.array([3, 4], type=pa.int64())}) In [3]: pa.concat_tables([t1, t2]) --------------------------------------------------------------------------- ArrowInvalid Traceback (most recent call last) <ipython-input-91-40afec1155a5> in <module> ----> 1 pa.concat_tables([t1, t2]) ~/.local/lib/python3.7/site-packages/pyarrow/table.pxi in pyarrow.lib.concat_tables() ~/.local/lib/python3.7/site-packages/pyarrow/error.pxi in pyarrow.lib.pyarrow_internal_check_status() ~/.local/lib/python3.7/site-packages/pyarrow/error.pxi in pyarrow.lib.check_status() ArrowInvalid: Schema at index 1 was different: a: int16 vs a: int64 ``` > [C++] Allow automatic String -> LargeString promotions when concatenating > tables > -------------------------------------------------------------------------------- > > Key: ARROW-7245 > URL: https://issues.apache.org/jira/browse/ARROW-7245 > Project: Apache Arrow > Issue Type: Improvement > Components: C++ > Reporter: Wes McKinney > Priority: Major > > inspired by GitHub issue https://github.com/apache/arrow/issues/5874 -- This message was sent by Atlassian Jira (v8.20.10#820010)